Nowadays, density of electronic parts and components on a Printed Circuit Board (PCB) is increasingly high from an end consumable to a system equipment, more electronic parts and components need to be installed in the same or even smaller space, and the demand for miniaturizing the electronic parts and components is increasingly strong. Quad Flat Non-leaded (QFN) packages have been widely applied in recent years gradually due to its small dimensions, small size, and high thermal and electrical performance.
In a prior art, there are two types of QFN package bodies. One is a QFN package form based on Package in Package (PiP), which applies plastic packaging twice to achieve stacking of a plurality of components in one package body; and the other is a QFN package form based on Package on Package (PoP), which uses means such as grinding to form an exposed weldable lead surface on a lower package body, thus implementing a package structure where one package body is stacked on another package body.
The prior art implements two layers of stacking, but the number of layers of stacked components is still limited, which has certain limitations. Moreover, all stacked components are placed in the package body, which leads to the low reliability of internal welding joints and a structure that is not concise enough.